Containers whose bottoms are vertically movable by the devices dealt with in this invention are collecting cans positioned downstream from machines carrying out combing and making preparations for spinning, etc. The continuous improvement of machines used in the conversion cycles or processes for combing, preparing for spinning and so on has raised output to very high levels. As an outcome of the considerable increase in output, the containers for collecting the slivers delivered by the machines have reached bigger and bigger sizes; at the present time the containers (cans) receiving the delivery have a diameter of one meter or more and a height of up to 1.2 to 1.5 meters so as to reduce the number of times the can has to be changed.
To avoid continuous work on the part of the machine operator in replacing full cans with empty ones, the machines have also been equipped with delivery means having devices that change the cans automatically. Even if the operation of changing the can is done by hand, it always takes place with the machine stopped, and therefore automatic changing leads to a considerable reduction in the time during which the machine is stopped and to a corresponding increase in the output of the machine.
In the various conversion processes such as combing, etc., although the machines are not alike, there are always more than one of them and each machine is usually fed with slivers produced by the preceding machine, these slivers being stored temporarily in cans. At the present time the replacement of cans on the creel of the machines is still done by hand. Thus arises the need to maximize the filling of the cans so as to reduce the operations required and thereby to enable each operator to take charge of more machines.
Accordingly, the problem to be solved continues to be the best way to fill the cans so as to efficiently utilize the capacity thereof, since their capacity is limited by their size.
The efficient system of depositing the slivers in the cans by means of rotation was perfected for this very purpose. This system usually provides at the delivery side of the machine a former head (swivelling feeder) which rotates and deposits the slivers in a can which itself rotates slowly and whose diameter is greater than the diameter of the circle formed by the slivers being delivered by the swelling feeder. The regularity of this depositing leads to correct filling of the can provided that the distance between the former head and the collecting bottom of the can remains constant within certain limits.
As said earlier, certain cans at the present time reach a height of 1.2 meters or more and it is therefore natural that the arrangement of the slivers is not properly controlled at the start of filling since there is a considerable distance between the former head and the storage surface at the bottom of the can. During filling, the coils or cycloids of slivers created by the rotation of the former head in coordination with the slow rotating movement of the can are disturbed during the course of the descent of the slivers, and deposition of the slivers on the bottom of the can takes place pell-mell in an irregular manner to the detriment of the filling. Regular formation of the cycloids only takes place when the can has been almost wholly filled pell-mell, and the slivers have reached a height such that they form an upper collecting surface which is very close to or is in contact with the former head.
Besides the above shortcoming, it should be borne in mind that, having machines with a very high delivery speed, it can happen that with material of a short length or fine slivers or slivers with a low consistency, the material itself will be torn away owing to the beating it undergoes during its journey from above to the bottom of the can.
The best filling conditions are obtained only when the surface supporting the material is at all times very close to or almost in contact with the swivelling feeder. For filling to be ideal, the material should also be slightly compressed.
In the processing of cotton, cans of small size are used with a maximum diameter of 600mm. and with a movable bottom which is pushed upwards by a spiral spring so as to prevent the tearing of slivers having a small section, low consistency and a high deformation speed, whereas in the processing of wool, cans of a bigger size and with a fixed bottom are employed.
Devices have been designed which enable the bottoms of the cans to be raised so as to keep the surface supporting the material that arrives from the swivelling feeder to be very close to the swivelling feeder itself at all times. In the present state of knowledge of the art, these devices are substantially two in number.
The first of these devices uses a plurality of pantograph elements activated by a mechanical element (a screw). The other device envisages a rod activated by an endless chain.
These two devices involve many shortcomings. The first device has an excessive height when the device is close up and moreover it does not permit fast lowering in case of an emergency. Besides the defects of the first device, the second device is also unsuitable for receiving rotation and transmitting it to the collecting bottom or plate.
These shortcomings entail many disadvantages. The first disadvantage lies in the fact that excessively tall devices of this type cause their users to provide holes to contain them, but such holes are not always feasible, particularly where the machines are not mounted on raised surfaces, and such holes may necessitate objects hanging from the ceiling.
Another disadvantage of these devices is that, in case of an emergency, the device itself cannot be made to withdraw quickly because of the mechanical means employed.
A third disadvantage arises from the fact that to ensure a homogeneous product, both the can and the bottom should rotate in a coordinated manner and, as this is not possible, one of the main features required by the storage system is thereby lost.
In the final analysis, all these shortcomings and disadvantages lead to a reduction in the output of machines linked to such known devices.
To obviate these deficiencies, which have substantially blocked and limited the use of such devices to specific duties, Applicants have designed and realized some improvements to such cans which have taken shape as improvements to devices that raise the bottoms of the cans, whereby there is a plate which slides vertically within the can and which is activated by an axially-extending pantograph, the improvements including fluid-type means which activate the pantograph vertically, a rotating plate which transfers the vertical drive from the fluid-type means to the pantograph means, and rotating means that support the pantograph, wherein the plate sliding within the can is independent of the bottom of the can itself.
These improvements are aimed at numerous objectives and advantages. One objective is for the storage plate to be able to be raised as desired and to withstand the material being stored with a pressure that can be preset to a desired value.
Yet another objective is that the bottom and the can should rotate at the same time in a coordinated manner.
A further objective is to employ the device with cans now in use without having to refit anew with non-standard cans.
One more objective is to realize a compact device with small overall dimensions which will need a substantially small accommodation area.
Yet another objective is to adopt pneumatic means which, by employing rapid exhaust valves, make it possible to ensure that, when the device changing the can rotates, the device which is our subject is below the paved floor line.
A further objective is to ensure that, if foreign or excess material should enter the can, the device itself will be able to put right the anomalies on its own independently; this, for instance, is not possible with mechanical devices inasmuch as their rigidity does not permit it.
Another advantage is the ability to have a drive with overpressure, the drive being provided with a valve that tends to keep the thrust of the plate against the material being stored almost constant; this is so because the position of the plate itself, and the thrust which it exerts against the material being stored, are strictly correlated and coordinated with the quantity of material entering.
It is an advantage not to have other mechanical devices to transmit and deliver motion, but to have only means to transmit pneumatic or hydraulic impulses.
A further objective is to be able to use indifferently a pneumatic or hydraulic drive, although a pneumatic drive is more advantageous.
To obviate difficulties which lead to an anomalous distribution of forces and thereby to a movement of the inner plate which is neither linear nor gradual nor desirable, the inventors have also provided a variation wherein the fluid-type raising means is fixed to the swivelling casing and this prevents a raising or lowering movement from obstructing the rotary movement. By eliminating any anomalous stresses, this variation enables a linear ascending or descending movement of the plate to be accomplished, such a movement being in conformity with the working requirements.
The invention, therefore, also consists of improvements to devices that raise the bottoms of cans whereby a plate slides vertically within the can by means of a pantograph that extends axially, said improvements including fluid-type means that activate the pantograph vertically and rotating means that support the pantograph, whereby the plate sliding within the can is advantageously independent of the bottom of the can itself and the fluid-type means that activate the pantograph vertically are advantageously solidly fixed to and supported by the rotating means that support the pantograph, and whereby there is also advantageously present a rotating joint means which delivers fluid under pressure.